Hi there BikerBabe
Like the others say, any increase in energy output will have an effect.

Technically, to lose weight consistently, you should be doing 3-4 25 minute aerobic workouts a week. Aerobic workout being where you lift your heart rate, but can still talk.
So instead of sauntering through the park, you walk briskly
Instead of pedalling at a slow cadence, use a lower gear and move your legs more quickly

I have been cycling for 18 months now. I have only dropped a few kgs in that time BUT I have dropped two dress sizes now. Very exciting and uplifting to donate three pairs of jeans to a charity op shop two weeks ago because they are too loose and buy myself a new pair of jeans!!!
So remeber that initially you may see no change on the scales - your body will respond by shifting the weight and building muscle...

Good luck... you know the girls will be 100% behind your goal. It feels so good to be fitter