COMING SOON: Looking Again at the Name Arthur

A very old problem for Arthurian scholars, this one: what is the origin of the name Arthur?

Many ideas out there, most invalid from a philological and/or phonological standpoint.  Conventional wisdom has it deriving from Roman Artorius, perhaps a decknamen for an Irish or British name. 

But I want to approach this from another direction.  We do not find the name in Ireland.  Purely British chieftains of the time did not choose it for their sons.  Instead, it is found only among Hiberno-British royal families.  WHY?

I will do my best to supply a reasonable answer to that question in the next few days.