I was exactly in the same situation once started checking my BGs about 2 years ago. i'm used to exercise and always did this first thing in am, of course, before I had anything to eat. I thought it's better to exercise on emopty stomack for weight loss.
since I've noticed that streneous cardio and weights along with any workout longer than 45 minutes pushes my BGs 60-70 points, I've made some adjustments to my routine. I still exercise in am (cardio mostly) but eat a small snack like a low GI fruit or some berries 10-15 minutes before exercise. this way i can be sure that Bgs eigher remain stable during exercise or be lower once I've complete my routine. fruit and berries are digested very fast and not disrupt my workout but they put breaks on a "liver dump". if for some reasons fruit is not acceptable, than try some PB or switch exercise time to after lunch or dinner. morning is when we are most IR, and hence, the higher BGs.
I also try not to go for longer than 45-50 minutes in one session and do weights before or after dinner, not too close to bed time. also, i've noticed that going at a lower pace (i do have ellptical machine) but incerasing incline and resistance works much better BGs wise and weigth loss as well.
walking uphill is very good option too. this is my personal experience, keep in mind YMMV. in any case, exercise is a life saver for me and for all diabetics.
Cheers,
Dina