Try clicking on the "Insert Hyperlink" icon (fourth from the left on the lower row). That will automatically insert the beginning and end of the necessary HTML language to insert a link. Then type in, or copy and paste, the URL you're intending to place in your topic message. When you hit Post, your link along with the name of the link will be inserted in your document, highlighted and ready for readers to use.
I've done that with
The Villages Daily Sun website right here
http://www.thevillagesdailysun.com/
Let's see if it works.