We have hundreds of posts on our company blog and our theme converts all the titles to uppercase letters. Lately we had one post the had a technical term in its title and we needed to force a lowercase character instead of cancelling the entire uppercase conversion altogether.
The solution that worked was: “TITLE WITH LOWERCASE <span style=”text-transform: none;”>d</span>”
WordPress shows the span tag in the editor, but viewing the page it does what it’s supposed to do – cancel the uppercase conversion.