You can calculate the moisture content of any wood pretty close by taking the average relative humidity along with the temperature over time. There are places on the internet that will do that for you. Just goggle "moisture content of wood" and look for the page to enter your average RH & temp and it will get you pretty close. The data below shows yearly averages, morning and afternoon far as humidity for your area, but in colder weather the humidity drops. I'd average the last three weeks or so on both numbers to find the moisture content. I'm not sure with red elm but I'd venture to say anywhere between 6 to 9% should be fine.
Maybe some of these other guys can help with that, just not experienced enough with red elm to know.
London, Ontario 86% morning-65% afternoon- yearly average (quick search) not sure about the temp.
Be sure to post your results.
Good luck and hope that helps.