Divide the rosé wine between 2 ice cub trays or pour into a shallow baking pan. Freeze overnight or longer. It's okay if the wine doesn't freeze completely solid.
In a small sauce pan combine the sugar and water. Heat over medium heat, stirring until the sugar is completely dissolved. Set aside to cool completely. The simple syrup can be made a day ahead and stored in the fridge.
To assemble the drink, add the frozen rosé wine cubes to a large blender. If the wine was frozen in a shallow pan, then break it up into small chunks and add to the blender.
Add the frozen strawberries, the simple syrup and the elderflower liqueur to the blender. Blend the mixture on low speed to break down the frozen wine and strawberries. Stop blending occasionally to scrape down the sides and push the frozen berries down into the mixture. Continue blending until the mixture is completely smooth and is a slush consistency. Divide between wine glasses and serve immediately!