I know this is doable in the offline editor, is there an option in the online?
Yes. It should be in exactly in the same place. When in the online editor, click "game" in the left side list and go to the "Room Descriptions" tab. There should be a line near the bottom that says "Use 'You are in' prefix (turn off to display room name in bold instead)". Just uncheck this box and voila! You're ready to go. Hope that helped!
Below is a screenshot of the correct screen to be on: