x86-16 machine code, IBM PC DOS, 13 bytes

00000000: b04c cd29 b86f 6ccd 2986 e0eb fa         .L.).ol.)....

Listing:

 B0 4C          MOV  AL, 'L'        ; start off with capital L 
 CD 29          INT  29H            ; write to console 
 B8 6F6C        MOV  AX, 'lo'       ; AH = 'l', AL = 'o' 
            PRINT: 
 CD 29          INT  29H            ; write AL to console 
 86 E0          XCHG AH, AL         ; swap 'l' and 'o' 
 EB FA          JMP  PRINT          ; loop forever

A standalone PC DOS executable COM program. Output to console.

Runtime:

Forever and ever...