If I walk up to the point where the exit from The Forest Of Tethir to Suldanessellar is, I can in fact go to the Elven city even without the Rhynn Lanthorn. This happened on Android (with the button for showing containers and points of interest active), will test PC version tomorrow. No mods installed, though I admit I have tampered with some files (also .are and .bcs files, but not this area file nor any of its scripts). Version 1.3.2064. As far as I can remember from the original, this shouldn't be possible.