Lord Harrowmont is involved in the side quest Last of His Line in Dragon Age II, if using an imported save where Bhelen was made king (note that if you choose The Martyr pre-built history Bhelen will be king).
Renvil is encountered at the Kirkwall Docks with his guards, surrounded by a group of Carta and Antivan Crow assassins. Once they are dealt with, Renvil asks Hawke to kill the rest of assassins blocking his escape and offers payment in return.The head of the first group of carta thugs, offers Hawke more gold for killing Harrowmont instead. If you decline his offer and kill the remaining thugs, Harrowmont will thank you and take a ship to Rivain, where he hopes to be safe. A letter from him will be received in 9:34 Dragon, telling Hawke that he is preparing to leave for Kal-Sharok before assassins catch up with him again.