Possible Clues:

• It adorns Senor's middle
• Accent has come about in Latinised literature
• Manet and Burroughs depicted the bare fact of it
• Squiggly mark in 'señor'
• Bit of Portuguese
• Spanish cedilla
• It's wavy in São Paulo
• Accent over n in Spanish
• Feature of 'se–or'
• Lord enthralled by Moor's Spanish accent