Just leaving a few URLs I've come across, but I haven't found a connection to the Grosvenor Hotel in Port Erin...

https://www.britannica.com/biography/Emile-Zola

https://www.heraldscotland.com/life_style/arts_ents/15023495.zola-england-review---disappearance-emile-zola-michael-rosen/

A Guardian article suggests it was actually Grosvenor Hotel in London:

"Early on the morning of 19 July 1898, Zola had stepped off the boat train from Calais, carrying nothing more than a nightshirt wrapped in a newspaper and the name of the Grosvenor Hotel on a bit of paper."

https://www.theguardian.com/books/2016/dec/28/emile-zola-french-novelist-christmas-south-london