Let's use the elapsed time since the last frame, to breathe life into the bee and the clouds. This will solve the problem of having a consistent frame rate across different PCs.
The first thing we want to do is to set up the bee at a certain height and a certain speed. We only want to do this when the bee is inactive. So we wrap the next code in an if block. Examine and add the highlighted code, then we will discuss it:
/*
****************************************
Update the scene
****************************************
*/
// Measure time
Time dt = clock.restart();
// Setup the bee
if (!beeActive)
{
// How fast is the bee
srand((int)time(0));
beeSpeed = (rand() % 200) + 200;
// How high is the bee
srand((int)time(0) * 10);
float height = (rand() % 500) + 500;
spriteBee.setPosition(2000, height);
...