This might help, http://gardening.stackexchange.com/questions/2488/how-long-does-it-take-a-mock-orange-bush-to-flower

just copy and paste into browser bar.

I have had similar issues with my Mock Orange. Bought as a 3 foot shrub 3 years ago. I did not prune it at all as I needed some height to cover a new fence. This year in early summer, as an experiment I decided to prune half the bush quite hard to see if it will spur any flowers next year. I did have one branch of the old wood that had FOUR flowers on it. Of course I accidently cut that out as I did not see it. Maybe we can pm each other next year to check on progress!!!!! I bought a lilac at the same time, I have left that alone in the hope that it will flower before I am in my box. I have noticed that mock orange growing wild along the railway line always flowers, but there is no way of knowing how old they are.

The time for pruning both of these is IMMEDIATELY after the flowers fade - next year's flowers will be on the wood produced during the summer, and that's why you prune straight away, so that there's time for more wood to grow. As you pruned at the wrong time last year, and didn't get flowers this year, its again too late to do them. If you can stand it, leave them alone, then prune immediately after flowering next year. If you can't stand it, prune back half the growth, leaving some intact.