Doran's Ring has been buffed a bit since season 10, it now grants 10 health more and its mana reget passive has been changed to give 6 mana on minion kill instead of bonus mana regen. Doran's Ring is a really solid starter on Orianna, as it empowers her early laning phase with its stats by a lot damage-wise compared to Tear of the Goddess or Corrupting Potion.

You should only start Tear of the Goddess if you're looking to hard scale as fast as possible and if you're not looking to fight or harass early anyways. The missing AP and health from Doran's Ring means that your early laning phase is slightly weaker.

The updated Dark Seal now gives 5 AP per stack instead of 3 and its 25% healing from potions increase has been removed. I would only start Dark Seal if I'm very confident in the matchup or my enemy has a terrible winrate. I usually pick up a Dark Seal on my first or second back if I have the money for it. Upgrading to Mejai's Soulstealer doesn't seem worth it anymore though, as it costs 1600 gold (1250 when already owning Dark Seal) when basically all it does is increase your maximum amount of stacks. (Last season Dark Seal only granted 3 AP per stack and Mejai's Soulstealer 5, so upgrading was worth it)

The new Luden's Tempest works very similarly to the old one. It's still built from Lost Chapter and Blasting Wand and it still got its echo passive. What's new, is that it now is an item from the type mythic. And as a mythic item, it grants a bonus stat for each legendary-type item (any non-mythic complete item) you own. Luden's Tempest grants 5 bonus flat magic pen per legendary item, which is very valuable for Orianna, as her main goal is to oneshot the enemies carrys in a teamfight. Besides of that, it now grants 30% movespeed for 2 seconds after proccing its echo passive, which helps Orianna kite.

Liandry's Torment is the reworked form of Liandry's Tornment. Its burn has been altered slightly and it now grants mana instead of health and is built from a Lost Chapter, just like Luden's Tempest. Liandry's Torment is also a mythic-tier item and grants 5 bonus Ability Haste (reworked, linear CDR stat) for every legendary item you own. This is also a perfect choice for Orianna as she benefits greatly from cooldown reduction with her already low cooldowns. The burn is also very useful for Orianna, as it burns enemies for 1% max health, perfect agaisnt tanks or bruisers with a ton of health. It also shreds magic restistance over time now, which helps even greater against tanks.

The new Archangel's Staff suits Orianna much better than the old one. You can now buy Tear of the Goddess lvl 1 as a starter, so you can go Tear of the Goddess and still spend your precious first-back gold on that Lost Chapter. Where you had to make a choice between scaling and stronger laning phase before, you can now go for both, and as far as I tested, it works super well on Orianna. When you hit your Luden's Tempest Archangel's Staff powerspike and Archangel's Staff is fully stacked, its passive will grant you about 100 bonus AP, bringing you to a total of about 300 AP with 2 items.

Cosmic Drive feels like it's just made for Orianna. It provides a little extra tankiness and AP and a ton of Ability Haste, but most importantly its passive gives you (10 + 20% Ability Haste) movespeed for 4 seconds whenever you damage an enemy using an ability. Now combine Phase Rush, the new Luden's Tempest movespeed and Cosmic Drive and Orianna becomes a kiting goddess.

Horizon Focus is a completely new item introduced to the game in pre-season 11. It grants you 10% increased damage for 6s against an enemy you immobilize or hit with in ability from 750 range away. Orianna's Q Command: Attack range is 825, so hitting a somewhat max range Q enables this effect already. But where this passive really shines, is when you hit a good R Command: Shockwave on multiple targets, these 10% can be the difference between oneshotting 3 enemies at once or only barely oneshotting them.

Not much to say here. Demonic Embrace is basically the old Liandry's Tornment with some tweaks to the burn effect. It grants health and AP and it's passive burns enemies for 1.5% max health. It also grants you resistances for each enemy currently burning as long as they're burning. No need to say that this is also great against tanks and bruisers. And, as Demonic Embrace's burn stacks ontop of Liandry's Torment's burn you can combine the 2 items if the enemies have one or multiple fed tanks.

The new Morellonomicon grants, like before, health and AP. But unlike before, it doesn't give you flat magic penetration anymore. The item now focuses entirely on Grievous Wounds (anti-heal). It now builds from a Blasting Wand, a Sapphire Crystal and the new Oblivion Orb. This is a huge quality-of-life change for mages, as Oblivion Orb only costs 800 gold now and grants 40% Grievous Wounds already. So just like a bruiser or an adc would pick up an Executioner's Calling for 800 gold to have antiheal and never finish it, mages can now do the same thing.

Rylai's Crystal Scepter grants a healthy amount of health and AP, but most importantly, its passive slows enemies hit by one of your abilities by 30% for 1 second. A Rylai's Crystal Scepter can be really good when your team needs some extra crowd-control, because your enemies are either extremely mobile or your team just lacks it.

Since the pre-season changes Zhonya's Hourglass probably won't be as essential on Orianna as it used to be. It does provide a lot of helpful utility with its stasis effect, especially if the enemy team has an assasin, but with all the new amazing options for Orianna I don't see it being built as often as before. It should be noted though, that Seeker's Armguard only costs 900 gold now instead of the former price of 1100 gold, so it can be picked up even earlier to counter assasins.

Banshee's Veil has always been a niche buy on Orianna because it packs much less utility than Zhonya's Hourglass does. Banshee's Veil grants you a passive spellshield with 40 second cooldown, so it's pretty good against hard engage like Zac or Vi.