Completing my listen of the boxed set of Borodin orchestral work, the 'light music' pieces often played by Rob Cowan etc, Classic FM and Radio 2's Friday Might Is Music Night, most enjoyable while I'm today stuck in the house myself doing accounts and ignoring the Grand Prix race. I will get out into the garden soon.
Petite Suite
Nocturne for String Orch (arr. Sargent)
Prince Igor: Overture and Polovtsian Dances
In The Steppes of Central Asia
Mlada
I'm intrigued by the popularity of the Nocturne, a beautiful arrangement of the third movement of Borodin's 2nd String Quartet, and whether Borodin himself wrote an orchestral arrangement - the Malcolm Sargent arrangement seems to feature in many available recordings. I also have a Neville Marriner arrangement on an Academy of St Martin's-in-the-Field album.
Edit: added so as not to interrupt the Mahler threadlet 
Reading the extensive notes in the Borodin boxed set, it's clear that I've also been listening to Rimsky-Korsakov and Glazunov!
They both edited and revised Symphony No 2, with a contribution also from Balakirev. Mlada and the Prince Igor music were unfinished by Borodin and much was orchestrated by Rimsky-Korsakov and Glazunov.
Glazunov reconstructed and orchestrated Symphony No 3, and the Prince Igor Overture, and he orchestrated the Petite Suite, from two piano works (he added on Borodin's Scherzo in A flat as the last piece).
That hasn't detracted from my enjoyment of all this Russian 'light' music, and I'm still intrigued about who first orchestrated the Nocturne.