HP Lovecraft and Theosophy
https://web.archive.org/web/20140815171353/http://www.crypt-of-cthulhu.com/lovecrafttheosophy.htm
found via another fascinating little potted summary of the general family relation between Masonic and Hermetic and Theosophical groups in the 19th/20th centuries:
https://www.reddit.com/r/AskHistorians/comments/6jcta6/the_twin_peaks_concept_of_the_black_lodge_is/