I'm not sure if there's a consolidated list, but the property websites have a "The health and safety of our guests is our top priority: COVID-19 updates and what to expect at our hotel" link which shows the status of the lounge.

Note though, that even when the lounge is "open", the offerings are severely reduced. The Sheraton Grand Park Lane, for example is "Lounge Access: Club Lounge open for self-service of hot beverages and chilled waters."