I spelunked the fvwm man page a bit and figured out how to uniconify a window from a shell script: FvwmCommand -r 'Next ("Lispworks", "Editor *") Iconify off'. Here's a new lwclient:
#!/usr/bin/zshFvwmCommand -r 'Next ("Lispworks", "Editor *") Iconify off'
(
echo "lwclient$RANDOM"
echo "(progn "
for f in "$@" ; do
if [[ $f = /* ]] ; then
echo "(editor:find-file-command nil #p\"$f\")"
else
echo "(editor:find-file-command nil #p\"$PWD/$f\")"
fi
done
echo ")"
) \
| nc -q 1 localhost 65000 \
> /dev/null