The current Lord Mayor of London is a Welsh man and as it is the fiftieth anniversary of Ysgol Cymraeg Llundain where my younger boys attend he kindly arranged a celebration there last night. The event was covered by the Welsh language proramme Wedi saith and if you go to the site(http://www.s4c.co.uk/e_watch_wedi7.shtml) at the moment you can see a package on the event (Wednesday c 1:50-9:30) including a brief interview with one of my sons (all in Welsh of course). The rest of the family went but I was not able to be there as it was prayer meeting night and I wasn't organised enough to rearrange things. The video shows Gwion's speech. You can spot Owain third from the right in the choir.
The similar phrase 'Worldly Christianity' is one used by Bonhoeffer. 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.