You might look at this page. It doesn't sound like Dutch Elm disease, which is generally associated with wilting, then browning, but there is a discussion of "Bacterial Leaf Scorch" and "Elm Yellows," which sounds similar. It's in the matrix about 1/2 way down the page.
http://www.na.fs.fed.us/spfo/pubs/h..._ded/ht_ded.htm
Of course the symptoms are consistent with root rot, too.
Regards,
Matt