Am I eliglible for VOA at Lo Wu station?

Sorry, you should apply for a L type in advance. Otherwise, you won't be allowed to go to Guangzhou. Or you may try to get the VOA for Shenzhen first. But you should understand that five-day special VOA just allows you to stay in Shenzhen. If you plan to visit Guangzhou, you should apply one from the entry and exit management bureau in Shenzhen before you go to Guangzhou.