The Collaborative International Dictionary of English v.0.48:

umquhile \um"quhile\ ([u^]m"kw[i^]l), adv. [Cf. OF. umwhile for
   a time. See While.]
   Some time ago; formerly. [Scot.] --Sir W. Scott. -- a.
   Former. [Scot.]
   [1913 Webster]