Arlo seems to have been created by the poet
Edmund Spenser for the name of a hill where the gods debate in his 1596 epic poem "The Faerie
Queen". Experts think the fictional Arlo Hill is the same as a real hill in
Ireland called Galtee More or Galtymore, and that Arlo is Spenser's alteration of Aherlow, the name of the glen which is next to Galtee More:
http://flickr.com/photos/8164399@N08/1548835335
http://www.tipp.ie/placesofinterest/aherlow-failte.htm
http://mountainviews.ie/mv/index.php?mtnindex=14