I'm not from Thedas, but I've been helping out after school at Skyhold with the horses as well.
My A horse that allows me to ride it occasionally stops by, so if you see a horse with a caramel coat and black mane that looks like he's probably judging or at least assessing you very closely and responds to Arion, you've probably seen him. He doesn't come all the time cause he kind of likes to be off doing his own thing.