A side issue, but I thought you shouldn't ever do this as it can damage your camera?
This is a myth. First off, can you imagine a company designing a camera that you had to shut off every time you changed lenses, because doing so would damage the camera? The warranty work would be staggering.
Beyond that, the camera is never really turned off, anyway. Try changing a lens with the camera off, while looking at the "card writing" light. Notice that it turns on briefly? Turning a camera "off" really just puts it to sleep.
I always thought the reason you should power off a digital camera when changing lenses is that when power is on the sensor is charged and will draw dust to it.
However when we use a zoom such as the 24-105 this pulls air in and out of the camera - which is probably why if you just use primes your sensor gathers less dust. Just a thought.
Also myths. The sensor doesn't generate a static charge, and it's behind the shutter, anyhow.
And as a sealed lens, the 24-105 doesn't really draw air into the mirror box. You can feel it pulling through the eyepiece, but it's unlikely that much dust will come through past the focusing screen.