The source of Lorgan's name is unknown, but it seems to be an Easterling name, and it seems to from the Irish Gaelic word for staff, "lorg", which reflects the noble position he held among Easterlings, or perhaps from the Scottish Gaelic name "Logan", which means "hollow", like a hollow in a tree. It's normal for people of pagan religions like the Easterlings presumably had to name their children after natural features.