Ariana Grande Eternal Sunshine tour review: pop illusion at its most effective – for good and bad

The O2, London On her last live dates before she steps back from the public eye, Grande holds her own – but it’s also impossible to avoid feeling concerned for her wellbeing There’s a thrum of excitement in the air as an eight-minute countdown starts and Ariana Grande’s unmistakable silhouette appears on a giant backlit curtain on the stage of the O2. Is it actually her? Posing there for eight…