Possible Clues:

• Danish architect Jacobsen
• Drury Lane Theatre composer
• Ex-governor Carlson
• 'Blow, Blow, Thou Winter Wind' composer
• Composer and arranger being oddly selective
• Barack Obama's Secretary of Education ___ Duncan
• Composer of 'Rule Britannia'
• Barack's Education Secretary
• Tuscan river
• Rule Britannia composer, d. 1778