I give up. When someone's gender (and species) is "angel," you can't call ilim sir or ma'am. (Yes, I'm practising. Shut up.) So what title do you use?
I'm being lazy and clinging to my copy of Lawrence of Arabia. Efendi it is.
(For the record, my three favourite movies ever are Lawrence of Arabia, Edward Scissorhands, and The Changeling. If you haven't seen them, I heartily recommend all three. Widescreen, HD. Especially for Lawrence.)