Arnulv was also at 57900, 57300 in the bottom right corner of the map near some axehands. We got the ring of the butcher we were looking for after killing him five times.
We also found Arnulv at 15900, 32400 and at the location listed. It seems as though the named werewolves in this zone can spawn in a number of different places, since none of them are where they are marked on the maps of malmohus. Apparently, from what we've seen, Arnulv spawns anywhere armguards are found.