After you've listened to Rodrigo and enjoyed him you look round for similar stuff and at some point in the nineties I bought this cassette of guitar concertos by Villa-Lobos and Castelnuevo-Tedesco. Very nice indeed. (Naxos do a nice CD with these two on it plus the Rodrigo).
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.