Michelle Obama has given the Queen an early birthday surprise by announcing she will accompany the US President when he has lunch with Her Majesty later this week.Mrs Obama has struck up a firm friendship with the Queen during her previous visits to the UK, and famously ignored royal protocol to put her arm around the monarch's shoulders in 2009. Until now, the US Embassy had indicated that President Barack Obama would be on his own for a private lunch with the Queen at Windsor Castle on April 22, the day after she turns 90.But Buckingham Palace has confirmed that...