Listen to the concert preview. Andris Nelsons is joined by countertenor Bejun Mehta and the Boston-based Lorelei Ensemble in the BSO's first performances of esteemed English composer George Benjamin's Dream of the Song, commissioned by the BSO for the 75th anniversary of the Tanglewood Music Center. Opening the program is Ravel's colorful orchestral version of his solo piano suite Le Tombeau de Couperin, inspired in part by the French Baroque composer François Couperin. Berlioz's Symphonie fantastique, his first masterpiece, is innovative in form, remarkably forward-thinking in its use of the orchestra, and quintessentially Romantic in its depiction of an artist's unrequited love..