A will o’ the wisp was originally a fictional creature like a fairy or an elf. They were bewitching lights or bits of colourful cloud/mist that would appear suddenly and entice people to follow them until suddenly they found themselves totally lost in unfamiliar surroundings…. so one meaning is what you stated above, but another connotation is “something hard to catch”, which definitely fits the Saint.
If you have seen the recent Pixar movie Brave, you would remember the little blue (?) lights which attract Merida – they are a kind of will o’ the wisp….
CAT-holics 
Sir , WILL-O’-THE-WISP acc to dictionary is an elusive goal.
How does ‘debonair will-o’-the-wisp’ fit in the context.?????
A will o’ the wisp was originally a fictional creature like a fairy or an elf. They were bewitching lights or bits of colourful cloud/mist that would appear suddenly and entice people to follow them until suddenly they found themselves totally lost in unfamiliar surroundings…. so one meaning is what you stated above, but another connotation is “something hard to catch”, which definitely fits the Saint.
If you have seen the recent Pixar movie Brave, you would remember the little blue (?) lights which attract Merida – they are a kind of will o’ the wisp….
regards
J
yup… when merida ventures into the woods to get that arrow….