Where can you find full elven in oblivion

The "Elven Armor" is held by Azani Blackheart who is located at a large Ayleid ruin called Atatar. You can find this ruin somewhere between Bravil and Leyawiin. Although Azani does not have a -Full- set of Elven Armor he has the most complete set you can get without having to be a high level. He is however very tough to beat.

Killing Azani Blackheart is part of a Fighters Guild quest called "Azani Blackheart". You will also find a Sinweaver on him which does Fire Damage and Drain Fatigue.