Would CF's Compare() function work for you? It does a
case-sensitive comparison of strings but I can see where it might
be an issue since you're looking to do the comparison during the
select.
Here's a link to an MS article that might help for doing
case-sensitive string comparisons at the DB level:
http://support.microsoft.com/?id=209674
Based on that article, something like this might be worth
trying (I don't have Access available to test so this may
completely bomb!):
<cfquery name="temp" datasource="lrs">
SELECT * FROM jobkeys WHERE StrComp(jobkey,"#ARGUMENTS.jk#")
= 0
</cfquery>
The thing I noted from the MS URL above is that the Asc()
function seems pretty useless. It only grabs the ASCII value for
the first character in a string -- not too helpful in a lot of
cases! StrComp() seems to be what you want but I don't know if it
will run inside of CFQUERY or if you have to add a function in
Access to accomplish this.