Possible Clues:

• Formerly, formerly
• Formerly (archaic)
• Previously, when there's a warning, of course
• When there's some prior warning, of course
• When to issue prior warning, of course
• Prior warning, of course
• A previous warning, then, of course
• When to give a previous warning, of course
• Previously get a warning then, of course
• When to give prior warning, of course