In the October 22, 2015 Interagency Flood Update webinar on slide 18 the speaker said that the Supplementary Information provides guidance on the term "lapsed" to mean the expiration date of the policy. Can anyone give me a link to that supplementary information, I am having difficulty finding it.

I believe they were referring to the preamble to the final rule:

https://www.fdic.gov/news/board/2015/2015-06-16_notice_sum_c_fr.pdf