Arelion's journal does not deal with any sort of scholarly studies.  It details his escapades with a young female blood elf!  How could I've been such a fool?$B$BUnfortunately, the floozy's identity is not revealed in this journal.  Aledis, a colleague of Arelion's, was his best friend and confidant.  Go question him and find out who he was having this affair with.$B$BI saw Aledis leave Falcon Watch for Zangarmarsh.  Follow the road headed north from town; it'll eventually lead west, toward Zangarmarsh.