See this thread: http://community.logos.com/forums/t/60100.aspx
User Richard Lyall found (with help of MJ Smith) that topics such as "Lord's Supper" are only found when using a "typographical apostrophe" (Alt 0146 numeric) as oppposed to the normal apostrophe we type with our keyboards. Only some entries like "Jude (Lord's brother") use the typed apostrophe.
Expected behavior: Logos uses one consistently and if this should be the "typographical" apostrophe, it automatically converts user input.