Bernhard Lang, Professor of Old Testament and religious studies at the
universities
of St. Andrews and Paderborn, provides the following material about the
name Yahu:
http://www.bibletopics.com/biblestudy/154.htm
Yahu
An alternative spelling and pronunciation of Yahweh, found (spelled YHW)
on a circa 800 B.C.E. ostracon from Kuntillet Ajrud and (spelled YHW and
YHH) in the documents written by Aramaic-speaking fifth-century B.C.E.
Jews living in Elephantine in Egypt. The form Yahu is also used in
biblical theophoric names (names that include the name of a god) like
Yeho-natan (Jonathan; Judges 18:30) and Yesha-yahu (Isaiah). Although
most scholars take Yahu to be a short form of Yahweh, it might also be
an earlier form of the divine name.3