Possible Clues:

• Punctual, as for a script
• When the script demands
• When expected 45. 47-Across in Italy
• End up putting chalk here before break, at the right time
• At the correct moment, like actor prompted to speak
• Precisely when called for
• Copper interrupts an individual at the right moment
• When signal given
• Willing to line up, we hear, promptly?
• At precisely the right moment