Postgresql – How can I get certain columns from a table only if they meet a condition in SQL?

I have the following tables:

CREATE TABLE books
(
    codBook INTEGER PRIMARY KEY,
    title   CHAR(20) NOT NULL
);

INSERT INTO books 
VALUES (1, 'Book 1'), (2, 'Book 2'), (3, 'Book 3');

CREATE TABLE people
(
    name    CHAR(10) PRIMARY KEY,
    address VARCHAR(50),
    CP      NUMERIC(5)
);  

INSERT INTO people 
VALUES ('Carl', 'C/X nº 1', '12345'), ('Louis', 'C/X nº 2', '12345'), 
       ('Joseph', 'C/Y nº 3', '12346'), ('Anna', 'C/Z nº 4', '12347');

CREATE TABLE lends
(
    codBook INTEGER REFERENCES books,
    member  CHAR(10) REFERENCES people,
    date    DATE,

    PRIMARY KEY (codBook, member, date)
);

INSERT INTO lends 
VALUES (1, 'Joseph', CURRENT_DATE - 10), 
       (1, 'Carl', CURRENT_DATE - 9), 
       (1, 'Louis', CURRENT_DATE - 8), 
       (2, 'Joseph', CURRENT_DATE - 10); 

I am trying to get all the rows with the title, address and CP where they were borrowed only if they were borrowed in CP=12345 and the rows that are not from CP 12345 to appear but without the address and the CP. As book 1 has CP 12345 and 12346, I only want it to appear with CP 12345.

My expected solution is:

"Book 1";"C/X nº 1";12345
"Book 1";"C/X nº 2";12345
"Book 2";null;null
"Book 3";null;null

I tried joining all the tables using 2 left joins:

SELECT title, address, CP 
FROM books 
LEFT JOIN lends USING (codBook) 
LEFT JOIN people ON (name = member) 
WHERE CP = 12345;

But I only get the rows with CP=12345 and if I remove WHERE CP=12345 I obtain all the rows, even the book 1 with CP 12346. I am looking for a way to solve this.