A Letter from Orsino is received at the beginning of Act 3 if Orsino was supported in the opening dialog.
Letter
You deserve your new title, despite what Knight-Commander Meredith might prefer. You and I both know what would have happened had you not been there to face the Qunari. I'm sure you've received no shortage of accolades from the powers that be in this city, but for what it's worth, I'm sending a gift from the Circle of Magi, too. Use it well.
Regards,
First Enchanter Orsino