"Much obliged. Ah, but--" He fell easily into step with her, "I'd thought I had at least seen all the Wardens here at Skyhold. But, don't believe we've met."

It's polite to at least know one's neighbors by name, if not in person. And Obi-Wan is many things, but only rarely impolite on purpose.

"I am Obi-Wan Kenobi, my position here is the Liason representing the Rifters."