The famous interview between Joan Bakewell and Dr Martyn Lloyd-Jones from 1970 is now up on Youtube and is well worth a view (over 2000 views already I see). I was surprised to see that it is in colour. So good to see it there.
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.