I am rather surprised that you would question your duke's decision to have the emperor act as his steward. Is that what you call loyalty nowadays?

Anyway, if I read the archives correctly, when the late emperor Siegfried embarked to Constantinople, Elberhard had acted as his steward for the position of chancellor and there did not seem to be much disagreement with that.

Seeing how this created a precedent, there is nothing wrong with emperor Elberhard assuming stewardship by the wishes of the current chancellor duke Arnold.