Here is the official policy (taken from the elite website not MI's intranet)

Guaranteed Concierge/Executive Club Lounge Access/Free Continental Breakfast*: at JW Marriott Hotels & Resorts, Marriott Hotels & Resorts, Renaissance Hotels, and Autograph Collection during normal hours of operations. For JW Marriott Hotels & Resorts, Marriott Hotels & Resorts, Renaissance Hotels, and Autograph Collection without a Concierge/Executive Club Lounge, Elite Members can still enjoy a complimentary continental breakfast for weekday stays, Monday through Friday; simply show Membership Card and room key in the hotel restaurant. *Not available at resort locations; weekday stays only

can be found here http://www.marriott.com/rewards/terms/elite.mi

On the intranet I find no changes to the policy - lounges are to be open Sunday evening through Friday Morning

If the lounge is closed during these times due to a holiday gold's and platinums SHOULD receive breakfast coupons