5 C.F.R. § 838.731 – Commencing date of payments.

(a) A former spouse survivor annuity based on a court order acceptable for processing begins to accrue in accordance with the terms of the court order but no earlier than the later of—
1. (1) The first day after the date of death of the employee, separated employee, or retiree; or
2. (2) The first day of the second month after OPM receives a copy of the court order acceptable for processing.
(b) OPM will not authorize payment of the former spouse survivor annuity until it receives an application and supporting documentation required under § 838.721.