Another thing, the rear tires on an elise are 255's while the fronts are 225's. Wider tires are more sensitive to camber changes, so maybe they are are trying to optimize the rear a little more for cornering, and not put so much camber correction in the front because they don't want to sacrifice braking; though, I don't recall the elise/exige's i have been in to have much body roll or pitch! but at the time, i wasn't really out to analyze the suspension either!
Its hard to analyze just the camber change because thats only one aspect of the system. I bet those lotus's run big caster up front; thats another thing that would lessen the need for a lot of camber correction in the front.
Our Formula SAE car last year had very little camber correction in the rear, and it was quite evident when standing behind the car as it powered out of a corner. in this picture, you can see the rear wheel going a little into positive camber and the tire really starting to be pulled under. I wish i had a better view of this, you don't see it too much from this shot. This year, more correction has been added to the design.