Arcade Fire's awesome manager Scott Rodger has confirmed the band is coming to Sweden. An announcement should be made early next week as to where and when. A Stockholm date is however ruled out.
I'd say the festival Way Out West in Gothenburg is a good bet.
Just to clarify: I'm only guessing Way Out West could be where they'll play based on their schedule and a few other things, but there are numerous other possibilities. Not even sure it's a festival date.