Possible Clues:

• Elegy far from cheerful about ploughman's end
• Song that's mournful, gloomy, with any number joining in
• Note part way through brooding solo
• Liaison's ending in emotional kind of poem
• A mournful song, especially performed by a single voice
• Byron's end portrayed in melancholy lament
• Knight in doleful song expressing sorrow
• Byron's end covered in gloomy elegy