"lobby lounge" is a correct and usable phrase in written English.
For example, you can use it in a sentence like this: "I met my friend in the hotel lobby lounge to catch up over a cup of coffee."
Suddenly the vastness of the lobby lounge comes into view.
A lobby lounge, Liquid, attracts a supercool clientele.
Better yet, a lobby lounge that serves cocktails.
In a fireside lobby lounge, sushi service starts at the après-ski hour.
Children's choirs will perform and there will be live music in the Lobby Lounge.
It will have a restaurant, lobby lounge, bar, fitness center and ballroom.
The view is even better from the Lobby Lounge of the old Regent Hotel (now the InterContinental) next door.
On Saturday there were food stalls selling dumplings; a D.J. played Japanese and American pop in the lobby lounge.
The in-house restaurant, Ellabess, is just off the lobby lounge, and also furnishes the hotel's room service.
There are five restaurants and bars, including a busy lobby lounge.
Breakfast is available in the lobby lounge, the bar or in the rooms, and other meals can be delivered.
