Two of the boys were playing guess that tune last night with the ipod and I happedned to hear just two opening bass notes of song and was immediately able to guess it. It was Come on Eileen by Dexy's Midnight Runners - not a song I own though a popular one and one I like. It's tribute to the writer's skill and a reminder of how much is in our brains that we are hardly aware of.
Bonhoeffer uses a similar phrase 'worldly Christianity'. It's J Gresham Machen that I want to line up most closely with. See his Christianity and culture here. Having done commentaries on Proverbs (Heavenly Wisdom) and Song of Songs (Heavenly Love), a matching title for Ecclesiastes would be Heavenly Worldliness. For my stance on worldliness, see 3 posts here.