Possible Clues:

• A card game for one player
• Quality of endurance in operetta
• Forbearance and long-suffering
• Virtue - card game
• Waiting calmly, as there's no one else to play this game
• That's the only virtue in Gilbert and Sullivan
• The virtue of Bunthorne's Bride
• Gilbert and Sullivan in hospital, by the sound of it
• Long-suffering head accepting nice break
• Solo card game, played with equanimity