HiB and OPT

I am graduating this August with PhD, and will begin to apply for my OPT this May. One company gives me an offer and will apply H1B for me in April so I may start to work in October. My questions are: 1. Will the BCIS start to PROCESS H1B application in April, or just start to RECEIVE H1B application, but will process the applications in October? 2. If the company submit my H1B application in April, and I submit my OPT application in May, will the H1B application makes my OPT application invalidate? Thanks a lot for your answer.