Arunel is not a real NPC, but if you ask Sentinels in Darnassus where the Archaeology trainer is they will tell you: "There is a scholar, Arunel, who can assist you." The real trainer is Lua error in package.lua at line 80: module 'Module:Factiongfx/faction_tip_link.json' not found. Hammon the Jaded <Archaeology Trainer> on the ground floor of the Temple of the Moon.