If I experience a mid-year qualifying life event that allows me to enroll in an HDHP with HSA, can I switch my General Purpose Health Care (GPHC) FSA to a Limited Purpose Health Care (LPHC) FSA?

No. Enrolling in an HDHP with HSA would not allow you to change or cancel your GPHC FSA election to establish HSA eligibility or to enroll in a LPHC FSA. Per IRS Notice 2005-86, an individual who is covered by a GPHC FSA is ineligible for HSA contributions for the individual's entire period of coverage under the GPHC FSA-even after the individual has completely exhausted a HC FSA balance. Coverage in a GPHC FSA will render the participant ineligible to contribute or receive any funds into an HSA for the entire plan year.