In Lightning Network, what are the proposals for solutions to transfers to offline end users? Basic examples in LN always mention payments from an online end user to other online end user. But let's say we want to send a micropayment donation to a blog that does not have an always online LN client.

With an on-chain transaction, the payer can send the money and the money will be there even if the payee can't check that within a week time. How about LN?

What are the current proposals for such payments? And what are the requirements for such end users who want to receive payments? Do we require the payee to get online at least once a day, once a week, or no such requirements are there?
Payments are handled by means of an established bi-directional payment channel.  While this may seem like a payment could travel in one direction to an offline participant in an open channel, in practice this would be difficult if not impossible.

The problem is that a channel exists as a protocol between two active participants.  There are no other computers involved.  If one of the two computers is not online, who does the sender send the transaction to?  Where is the transaction stored after the sender goes offline, but before the recipient comes back online?  In Bitcoin, these problems are solved by relay nodes and miners.  Once a transaction is in the mempools of enough nodes, the sender does not have to worry about retransmitting a transaction.  The point-to-point nature of the lightning network does not allow for this.

A work around could be a payment service, which is always online to receive and send payments on behalf of a user (for a fee, of course).  Another option is simply sending a regular Bitcoin transaction to an offline recipient.