yes, you can apply for a visa on arrival at the border. For Hong Kong visa, you can submit appropriate application forms relating to the purpose of entry to Hong Kong, together with the relevant supporting documents to the Immigration Section of the Office of the Government of the Hong Kong Special Administrative Region in Beijing (Beijing Office). If you are living outside Beijing in other provinces/cities of Mainland China, you need continue to send completed application forms by posts directly to the Hong Kong Immigration Department.
For HK visa, it normally takes 4 to 6 weeks upon receipt of all necessary documents to process a visa/entry permit application.