I typically use a manual setting with a wireless remote switch. The controller mounts on the spot where the external flash would go. There is a sync wire from it to the camera. I use a 2.4ghz wireless remote, although not required, but I tend to pull on the wire, causing camera shake. I want the least amount of problems there
The radio gets through almost every situation I need, and I've been over 40-50 feet away from the camera and have been able to continue to shoot.
You could go the other route, as you mention, where you take a shot every second. Still no guarantee that you'll catch the lightning, as it likes to do, the flash comes in between the closed and opened shutter ... Plus, you'll have lots of frames to look at, to see if you caught something. On the other hand, that is exactly what I do, when I want to make a Time-Lapse move, but that is another subject ... I digress.
As you mentioned, a tripod is a must !
Since you are using the Rebel, you can buy at least a wired remote for it. You'll want to get a bright lens to use, as close to f1.4 as possible. If not, use the widest f-stop possible to get as much light into the camera as you can. Even though the lightning is bright, if you have it set at let's say, F11 or F14, you might catch little or nothing at all. Even F4 would be better. Change the setting to M for manual. This will allow you to control how long the shutter remains open. As I mentioned, I shoot many times between 30 seconds and 5 Minutes. Keep in mind how bright the sky is. If it is really bright, even just sunset, then you won't be holding the shutter open for more than a few seconds. Dark skies are the key. Experiment.
Get a stop-watch to keep accurate time, so you don't overexpose. Your camera will pickup light you didn't know was there
You'll still have to do some trial and error, but this will cut it down some. Even with that said, I don't always catch the lightning. My lens is not pointed at or in the direction of a bolt that came down. Or, no bolts came down while I had the shutter open, etc. I have plenty of lightning-less frames, probably more than I capture. But, when you get it mastered right, you'll end up with 3 to 6 good photos from a shoot.
Since I love radios, I thought it was a perfect fit to use the 2.4ghz remote. You'd have to see if such an animal exists for the Rebel, as my remote would not work on your camera.
Have fun,
Here's a shot from last night near Willcox, Arizona. It combines the setting sun off to the right, not visible, and an approaching storm over the mountains ... This requires a little more experience to capture, but it is easily done, once you understand the hows and whys