The Eastern and Western Churches formerly did right to left; over the last millennium, the practice in the West has gradually changed. Pope Innocent III ca. 1200 gave the instruction for right to left. Was not able to find a good explanation for the change.
That was lousy wording.
I meant to say that the Orthodox still to this day do right to left. Perhap Ahhhnuld was influenced by the Orthodox in his life. In Europe, the wedding band is normally worn on the right hand, as well.
My guess is that Arnold doesn’t cross himself regularly, and when called upon to do it in public, might easily be confused. OR, maybe that is the way they do it in Austria.