At least on the NG I've always been told (during my initial course) that this is one of the differences between this acft and previous models (Classics), there is no kind o mechanical connection between the thrust levers and the engine itself !
So, as long as I know, the lever is supposed to remain exactly where it was at the time of the failure.
I'm not sure if the FCOM says something about that, but I'll search...
By the way, the "Engine Limit, Surge or Stall NNC contemplates this kind of failure" (Loss of Engine Control).
