You could possibly cbl search the name he had before and look at the clan that he is in. And look through the clan's members list and friend all of the similarly ranked people as the one showing on the cbl and ask if they know you.
If you remember his clan, You could search the clan in game, Find out the leaders IGN, Then log off and search the clan on the website. You could possibly find him that way. Or add the leader and ask him if he knows.