Soften the gelatin sheet in a bowl of cold water. Set aside.
In a small saucepan, heat the cream with the crumbled blue cheese until the cheese is melted.
Add the drained gelatin sheet and mix well
Divide the mixture into glasses and refrigerate for 1 hour.
Peel and core the pear, then cut it into small cubes.
Pour a little lemon juice over the cubes and mix well. This will prevent browning.
Separate the mixture into the glasses.
Finish the glasses by covering the small pear cubes with chopped arugula.