From my read of the situation, the answer is Auguest 2nd.
Please note, however, that Google Answers is not a source of
professional advice in matters such as this (see the disclaimer at
page bottom). Still, the law and guidance on COBRA does not seem to
set any minimum amount of time that coverage must have been in place
prior to a change in status.
You can read about COBRA coverage at the Department of Labor website:
Frequently Asked Questions about COBRA Continuation Health Coverage
As long as your workplace is covered by COBRA (and you should confirm
this to be the case!), then the following requirements apply:
--"A qualified beneficiary generally is an individual covered by a
group health plan on the day before a qualifying event who is either
an employee, the employee's spouse, or an employee's dependent
Note the "day before" language. In other words, you're covered on
August 2nd, if you had insurance on August 1st.
--...Qualifying events are certain events that would cause an
individual to lose health coverage...[including] Voluntary or
involuntary termination of employment for reasons other than gross
Quitting a job voluntarily is countd as a "qualifying event".
So, in sum...
--double check everything with a human resources professional, but as
far as I can see...
--if you're at a workplace covered by COBRA, then you should be able
to resign the day after your insurance becomes effective, and be
eligible for a COBRA extension.
Let me know if there's anything else I can do for you on this.
search strategy -- google search on [ cobra insurance ]