Among the tremendous pleasures of the Portsmouth Institute’s annual conference are the musical interludes. (Of course, I write that as a high-culture junky who can rarely afford a fix.) Friday night’s concert feature music by Edward Elgar was no exception. The first three clips feature selections from Elgar’s song cycle “The Dream of Gerontius,” based on the poem by Cardinal John Henry Newman, and the rest feature an Elgar composition for string orchestra. The former were performed by Jeffrey Nardone (tenor), Kara Harris (mezzo-soprano), and Michael Kregler (piano), and the latter by the Portsmouth Institute String Orchestra.