1. lets see some animal facts.
Lionesses are faster than males and can reach maximum speeds of 35 mph (57 km/h) on short distances of the order of approximately 90 meters, and a top speed on 50 mph (80 km/h) for 20 meters.
I am considering that it was a male Lion since you didn´t said otherwise. So they are heavier bulkier and get tire faster. Also they are very lazy.
Kangoroo. The comfortable hopping speed for a kangaroo is about 21–26 km/h (13–16 mph), but speeds of up to 71 km/h (44 mph) can be attained over short distances, while it can sustain a speed of 40 km/h (25 mph) for nearly 2 km (1.2 mi). The faster a kangaroo hops, the less energy it consumes (up to its cruising speed).
A Kangoroo can run faster for longer periods than an elephant so this particular kangorro is being an a*hole he could easily overpass the elephant.
Elephant. The biologist John Hutchinson, in workbench a real record in 2002, by organizing a running with 42 elephants, the fastest reached 15 mph (24 km/h) on average during the sprint, by knowing that he weighs only 3 tons (what is little compared with an African elephant which must be even less fast). In the short period, values as a top speed 25 mph (40 km/h), the elephant it is to run, but if we compare him with the other animals, he is not very fast
So the kangoroo is mantaing the speed of the elephant, therefore i confirm he is the a*hole of this question.
A horse can mantain up to 1 to 2 miles. So: We just need to wait until the lion tires or until he decides that the run doesn´t worths the effort.
2. Jump on the elephant and ride him instead
3. Snap out of the dream