Web links no longer work in LibreOffice 5.2.4 (Writer)

I upgraded LibreOffice on January 2nd and now, when I do a ctrl-click on a web link, firefox is no longer invoked. Before, either FF was launched or (if it was running already) an extra tab appeared within it. Curiously the link in the text does change colour, which suggests that LO thinks it has invoked FF. -- H Russman